There is an issue in 1.22 that has been addressed for the next release...
For the RSP2 there is a RF gain range step at 420MHz - if max gain is selected whilst trying to go over this boundary, SDRuno will return a tuning error. It will only happen going from low to high (i.e. from lower than 420 MHz to above 420 MHz) - when changing the frequency in the other direction, this should not be an issue.
(it may appear at a lower frequency than 420MHz if you are scrolling quickly because of the frequency update to the screen)
There is a similar RF step for the RSP1A at 1GHz (going low to high) and 60 MHz (going high to low)
If this is not what you are seeing, please raise a ticket at
https://www.sdrplay.com/support and we'll have a look at the problem.
Best regards,
Andy